The present invention relates to a method of operating a drive device, and to a corresponding drive device.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
A drive device of a type involved here can be used in a motor vehicle to provide a torque for powering a motor vehicle. The drive device may be a purely electric drive device which has one electric machine or several electric machines. The drive device may, of course, also involve a hybrid drive device which has different drive units, with one of the drive units being an electric machine. Another drive unit may involve an internal combustion engine.
When a hybrid drive device is involved, at least two drive units jointly provide, at least temporarily, a drive torque of the drive device and thus are linked to one another or can be linked to one another. Of course, the electric machine of the drive device may also represent merely an auxiliary power unit or an auxiliary drive, for example as starter for the internal combustion engine and/or as generator which is powered for example by the internal combustion engine and/or kinetic energy of the motor vehicle.
The electric machine may also be a component of a torque-vectoring device for example, in particular when several axles of the motor vehicle are operatively connected or can be operatively connected via a superposition unit. The electric machine is associated in this case to the superposition unit for example and distributes the torque to the axles. In principle, any drive topology of the motor vehicle may, however, be selected. For example, the motor vehicle may involve a BEC motor vehicle (BEV: Battery Electric Vehicle) and be powered by a wheel-hub drive or a fuel-cell drive. When the hybrid drive device is involved, a serial, parallel or power-split variant may be realized.
Especially when a purely electric drive device is involved, but also in the case of a hybrid drive device when operated solely by the electric machine, noise emission of the drive device is substantially reduced compared to the engine noise of an internal combustion engine. A driver as well as persons in the surroundings of the motor vehicle are not accustomed to this. In particular, they lack the possibility to use noise emissions or operational sounds of the drive device to make a determination about the rotation speed and thus indirectly about the travel speed of the motor vehicle.
It would therefore be desirable and advantageous to provide an improved method of operating a drive device to obviate prior art shortcomings.